Caption: Orchid flower (Calanthe tricarinata). One of the petals (red) is a specialised structure called a lip. This attracts pollinators to the flower, and acts as a landing platform. Calanthe orchids are terrestrial orchids (ones that grow in the soil), and are mostly found in the tropics of Asia, and also in Africa and southwards to Australia. There are more than 30,000 species of orchids worldwide, many of which are grown as ornamental flowers.